Switch hook for substation telephone instruments



.lmz. 1925. 1,540,260

' J. ERICKSON SWITCH HOOK FOR SUBS TATION TELEPHONE INSTRUMENTS Filed y 23, 1921 ZSImets-Sbeet 1 V Jmhn Ermksnn June. 2, 1925. i 1,540,266 I J. ERICKSON SWITCH HOO'K FOR SUBSTATION TELEPHONE INSTRUMENTS Filed May 5, 1921 2 Sheets-Sheet 2 LEI 5 I u 4* I am @"Iflm I FL nmlm Juhn Ermksun iit) Patented June 51?, 1925.

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JOHN nnIcKsoN, or cnrcneo, rntmors, Assrsrton re rin'rolvmrro ntncrnrc corr- PANY, or cnrcaeo, rumors, A oonroaarron" or ILLINOIS.

swrron: noon ren snhsrarron rnnnrnonn INSTRUMENTS.

I Application na May 23, 1921. "Serial No. 471,690.

To all whom it may concern: 7

Be it known that I, JorrN ERIGKSON, a

citizen of the United States of America,

anda resident of Chicago, Cook County,

and State of Illinois, have invented certain new and useful Improvements in Switch Hooks tor Substation Telephone Instruments, otwhi ch the following is a specification. v

The present invention relates to switchhooks for substation telephone instruments, and has for its object the production of a novel switch-hook of simple design which operates according to a new principle, and

which is free from certain detects inherent in prior switclnhooks.

on the exchange switches as the calling of the digit ones When this happens, if the calling subscriber is unaware of the fact that a preliminary impulse has been sent and does not replace the receiver again long enough to allow the automatic switches to restore themselves to normal position, he does not obtain connection; with the number for which the calling device is subsequently turned.

fore, is to provide a receiver switch-hook which, when used-1n automatic telephone systems, successfully prevents the sending of a preliminary impulse to the automatic switches when the receiver is removed from thehook.

The invention wlll bedescribed wlth reference to the accompanying drawings-yin,

which Figs. -1- to 4, inclusive, show the preferred form of the. invention as applied to a desktelephone, while. Figs; 5 to 8,inclu-- sive, show a desirable modification. 7 Referring nowparticularly toFigSi- 1 to 34, inclusive':', Fig. 1 is a front view of a desk stand, equipped with a; switch hook; built" according to the principles of the invention,

with the (transmitter support and tubular stand shown broken ofl above and below.

The tubular stand is showncut away so as to give a view of the parts contained therca in. Fig. 2, a similar view, is drawn as seen from-the right side, and with the receiver in place, Figs. 3and 4 are details, showing the construction of the hook and its supporting means. V

In Figs. 1 and 2, the tubular stand 2 its over the transmitter support 3 and bears against. a shoulder-formed on the latter, as is clearly shown in the drawing. The inner plate 4 is fastened to the support 3 bymeans of the screws 13 and 14:. This form of construction is wellknown and is in common use.

. -The bushing or bearing 5 is screwed into threaded-holein support 3, as; can be more readily seen in Fig. 8, which is a vertic'al section through the centre of the switch-hook 6. Fig; 3, that the screw 11 fits into'agroove so cut and situated as to holdthe hook 6 inplace with respect to sliding lengthwise in thebearing 5;, This groove is made long enough toall-ow the hook 6 to turn in an arc of ninety degrees, or a quarter of a. circle. This can be seen readily in Fig. 4, which is an enlarged cross section of the hook 6 on a line that passes through the centre of screw 11.,

The springs 8, 9, and 10, beingsuitably insulated, as shown, are mounted on a' projection 15 of; the plate 4, the said projection being turned; up so as to form a right angle with the said plate. against the hard rubber, roller -7,- which is when the receiver is lifted andmoved away from the hook the latter, propelled bythe (heavy spring 9, turns in a clockwisedirection thru an arc of ninety degrees, It will -be seen that at the beginning'of the move- The spring 9 bears It can be seen further in a fit;

v v rotatably. mounted on the crank formed by V A special object ofthe invention, there-;

merit the spring 9 moves very much slower than; the centre of the rubber roller 'Z, and much slower therefore, than the prongs of the switch-hook; and alsoit is seen-that the further the switch hook moves the" faster the spring 9;moves with regard tothecentre of the rubber roller, until near the end of the receiver is removed, it is lifted up andthe line spring the movement the two are moving at ap proximately the same speed. -Just before the switch-hook is stopped by the end of the positioning screw 11 (see Fig. 4:) the spring 9 comes into engagement with the spring 8, thereby closing the usual bridge across the line conductors. This is done at the time when a given movement of the switch-hook is accompanied .by the great.- est amount of movement in the propelling spring. The parts are now in the position shown in Fig. 1.

It is now plainly seen that, since the receiver is removed by lifting it vertically off, as is done when the ordinary hook is used, and since the. line contacts are not closed until the hook has rotated nearly ninety degrees, the source of preliminary impulses has been entirely removed, owing to the fact that the hook cannot rotate sufficiently to allow the line'contactsto close until the receiver is entirely removed therefrom. It is seen also that this result is accomplished without complicating the mechanism in any way.

In hanging up the receiver, the subscriber turns the same to a horizontal position with the end in which the diaphragnris mounted nearest him, inserts the opposite endfbetween the prongs of the hook, and then allows the receiver to assume a vertical position.

Referring now to the drawings comprising Figs. 58, inclusive, which show amodification of the invention, the general construction oi the desk stand shown therein is the same as the general construction of one shown on the first sheet. Figs. 5 and 6 correspond to Figs. 1 and 2, respectively, and Figs. 7 and 8 are details of the hook and support.

The sleeve 52, threaded at one end and screwed into the transmitter support 50, is shaped and recessed at the other end, as is most clearly seen in Figs. 7 and 8, so as to receive the movable hook 54k which is pivoted on pivot 53. There is a slot cut in the lower end of the hook 54. The rod 59 is pivoted in this slot at one end as shown in Fig. 7, and through the medium of the insulating bushing 55 is connected with the heavy line-spring 57 at the other end.

With the receiver in place as in Fig. 6,

57 is forced over into engagement with the bell spring 58. When out in the usual manner.

The switch hook immediately begins to rise under the in-- fiuence of the heavy line-spring 57." At the beginning of the movement the distance covered by the upper end of spring 57 ,for a given movement of the switch-hook, is very small, the point where the rod 59 is pivoted to the hook 54 being just a trifle below dead centre. As the movement progresses, the distance covered bythe upper end of spring 57, for a given movement of the switclrhook, steadily increases until it reaches its maximum speed just before the hook reaches the position indicated in Figs. 5, 7, and 8.

Just before the hook is stopped by its striking against the back end of the notch cut in the sleeve 52, or approximately at the time when a given movement of the switch hook is accompanied by the greatest movement of the line spring, the springs 57 and 56 make contact, thereby. closing a directcurrent bridge acrossthe line conductorsin the usual manner.

In this case, as in the preceding one, a preliminary impulse cannot be sent to the exchange switches accidentally because it is impossible for the line contacts to close until the hook has rotated nearly ninety degrees, which it cannot do until the receiver is entirely removed therefrom.

Vhen the, receiver is replaced by turning it into a horizontal position and inserting the proper end between the prongs of the hook, the said hook, together with the springs 5658, inclusive, assume normal position under the weight of the replaced re ceiver.

Having fully described'and ascertained the features of the invention, what is 'considered to be new and desired to have protected by Letters Patentwill be pointed out in the appended claims.

What I claim as my invention is:

1. In a telephone set, a receiver, a switch hook for supporting said receiver, means for pivotally supporting said hook to permit the same to move through an arc of approximately ninety degrees when the receiver is removed, a movable contact spring, and means on the switchhook for operating said spring and in such a manner that the ratio between any specified movement of the hook and the resulting movement of the said spring increases as the hook moves from its initial position.

2. In a telephone set, a receiver, a switch hook for supporting said receiver, means for pivotally supporting said'hook to permit the same to move through an arc of approximately' ninety degrees when the receiver is removed, a movable contact spring, and means on the switchhook for operating said spring at one rate of movement which is relatively small in proportion to the rate of movement of the hook as the latter begins its movement, the ratio between said rates continually increasing as the hook moves.

3. In a telephone 'set, a switch hook for supporting the receiver, means for pivotally supporting said hook to permit the same to move through an arc of ,approximatel said switchhook for operating said spring, the rate of movement of said sprmg increases with the function of the angle through which the hook is turned.

4. In a telephone set, a switch hook for supporting the receiver, means for pivotally supporting said hook to permit the same to move through an arc of approximately ninety degrees when the receiver is removed, a movable contact spring, and means on the switch hook for operating said spring, in such a manner that the distance traveled by said spring increases as the versed sine of the angle through which the hook is turned plusninety degrees minus said arc.

5. In a telephone set, a switch hook for supporting the receiver, means for pivotally supporting said hook to permit the same to move through an arc of approximately ninety degrees when the receiver isremoved, a movable contact spring, and means on the switchhook for operating said spring, such that with a uniform velocity of the hook the velocity of the said spring at any instant is proportionate to the sine of the angle through which the hook has been turned plus ninety degrees minus said are.

6. In a telephone set, a vertical tubular standard, a transmitter head protruding from said standard at the upper end there of, a horizontal member rigidly attached to said head and extending through one side supported on said member, contact springs insidesaid standard, said switchhook having a part passing through said extending member to control said springs.

7. In a telephone set, a vertical tubular standard, a transmitter head partly enclosed within the upper end of said standard, a horizontal tubular hook support rigidly attached to said head and extending through one side of said standard, a switch hook having a shaft extending through said support, contact springs inside said standard, and a crank on the inner end of said shaft for controlling said contact springs.

8. In a telephone instrument, a tubular standard, a transmitter head protruding from said standard at the upper end thereof, contact springs within said standard, a receiver hook pivotally secured to said transmitter head and rotatable about an arc in a plane parallel to said standard, and means rotatable on an axis eccentric with the axis of said switchhook for operating said springs when the said switchhook is rotated.

9. In a telephone instrument, a receiver hook, a transmitter support having a transmitter pivotally supported thereon, and means for rotatably securing said receiver hook tosaid support with its axis lying in a plane parallel with the axis 01": said transmitter hook. v

In witness whereof, I hereunto subscribe 7 ,my name this 16th day of May, A. 1)., 1921. of said standard, a switch hook pivotally" JOHN nnroxson. 

